1. Field of the Invention
The present invention relates to a method and a device for graphically illustrating the profile for filling a cigarette notably in order to control the strengthening amplitude and the position of strengthened tips relatively to the cut of the stem.
2. Description of the Prior Art
Generally, it is known that cigarette manufacturers have been lead to reduce tobacco density in cigarettes for economical reasons.
The two following questions were then raised:                how to retain proper resistance of the tips,        how to retain proper assembling quality.        
The retained solution for solving both of these problems was to retain the initial density for the tips (or even strengthen it) and to only reduce the density in the middle of the tobacco section.
It then became necessary to control the strengthening amplitude and the position of the strengthened tips as compared to the cut.
The applicant therefore developed a device for analyzing the filling of cigarettes called ARC, meeting this need.
This device was designed in order to axially displace the cigarettes in a tubular component comprising two diametrically opposite coaxial ports, i.e.:                a first port for emitting radioactive radiation (β radiation) from a radioactive strontium 90 source, and        a port for receiving this radiation located facing an ionization chamber connected to a measuring circuit with which the attenuation of the β radiation may be measured after its passing through the tobacco, it being understood that this attenuation is a function of the density of the material crossed.        
In this device, a stepper motor drive system causes displacement of the cigarette inside the tubular component. The measuring circuit is then driven in order to record at each step the density of the material crossed by the radiation in the axis of both ports.
This technology was abandoned subsequently because of constraining regulations relating to the handling of radioactive elements.
The applicant then developed another solution consisting of having the cigarette passed through an hyper frequency tuned cavity having a relatively low active thickness, for example of 3 mm. By combining the shift of the tuning frequency and the attenuation of the radiated signal when the cigarette passes through the cavity, it is possible to plot the density profile of the tobacco section of the cigarette.
In one case as in the other, the measured density values are used for obtaining the plot of the density profile of the cigarette.
Nevertheless, the visual interpretation of the plot of the density profile in order to determine with sufficient accuracy the position of the strengthened tips relatively to the cut of the stem and the strengthening amplitude is found to be difficult and uncertain as it depends on the operator.